1. Field of the Invention
The present invention relates to a rotating device that has a shaft fixed to a fixed body.
2. Description of the Related Art
Disk drive devices like a hard disk drive are well developed for reduction in size and increase of a volume, and are built in various electronic devices. In particular, such disk drive devices are nowadays built in portable electronic devices, such as a laptop computer and a portable music player. In comparison with disk drive devices built in a so-called stationary electronic device like a desktop PC (Personal Computer), resistances against shock and vibration are necessary for disk drive devices built in such portable electronic devices so as to withstand against a shock due to a falling and a vibration during a carriage.
For example, JP 2009-162246 A and JP 2010-127448 A disclose motors having a shaft fixed to a base plate and having a bearing that employs a fluid dynamic bearing mechanism.
According to the conventional shaft-fixed motors disclosed in JP 2009-162246 A and JP 2010-127448 A, a dynamic pressure generator is formed in the direction of a rotation axis R so as to be held between two tapered seals. According to this structure, however, when the thickness of a motor is restricted, it is necessary to reduce the dimension of the dynamic pressure generator in the direction of the rotation axis R. This reduces the rigidity of a bearing and harms the resistances of the motor against shock and vibration.
Alternatively, it is necessary to reduce the dimension of the tapered seal in the direction of the rotation axis R. In this case, in order to maintain the lubricant retaining amount by the tapered seal, if a space in a radial direction is increased, capillary force becomes poor. When the capillary force by the tapered seal becomes poor, the lubricant often leaks out.
Such a technical issue arises in the cases of not only the motors but also other kinds of rotating devices, in particular, a rotating device having a shaft fixed to a fixed body and employing a fluid dynamic bearing.
The present invention has been made in view of such a circumstance, and it is an object of the present invention to provide a rotating device which allows improvement of the rigidity of a bearing or which reduces the leak-out of a lubricant.